Heatable liquid container for a motor vehicle

ABSTRACT

A container ( 15 ) with a wall for accepting a liquid to be warmed in a vehicle, whereby the container ( 15 ) features a heating element ( 16 ), is characterized by the heating element ( 16 ) being fed from an electrical source of energy.

The invention pertains to a container with a wall for accepting a liquidto be warmed for a vehicle, whereby the container features a heatingelement.

Containers of this type are known which supply a feature in a motorizedvehicle (such as an automobile) with a liquid, in particular a liquidfor a washing system for washing the windshield or rear window panes orthe front headlights or signal lights of a motorized vehicle. Dependingon the weather, the driver needing a clear view must turn on thewindshield wipers.

He or she may also want to melt frozen washing fluid by suitable means,in order to melt fluids at temperatures under 0° C. or even lowertemperatures. (At these temperatures washing fluid may be frozen, evenif it includes an additive which lowers the melting point.) However, itsometimes occurs that the car driver forgets to add a sufficient amountof antifreeze or that very low temperatures are encountered, for whichthe amount of antifreeze in the washing fluid does not suffice.

The following suggestion has already been made. By means of a stainlesssteel apparatus similar to a immersion heater, frozen washing fluid isinserted from above into a container for windshield wiper fluid, via thelid of the container. Heated radiator water passes through the frozenwashing fluid. This solution of the problem proves to be awkward andexpensive.

From DE 44 25 214 A1, a container is known for a windshield wiper systemwith a chamber for accepting a washing fluid. The known container ischaracterized by featuring at least one additional chamber, separatefrom the washing fluid chamber, through which a heating fluid (such aswarmed radiator water) flows in accordance with the principle of a heatexchanger. The chamber can be shaped like a channel, or for exampleseveral channels or ducts for the heating fluid can run through thecontainer. The heating fluid chamber is preferably connected with theengine's cooling circuit, so that the heating fluid is available whenthe engine is running, in order to thaw frozen washing fluid.

For example, the heating fluid chamber is formed at the bottom of thecontainer, where it is located between the bottom wall of the containerand a separating wall, which separates it from the washing fluid chamberabove it. Hence, the heat exchanger is located nearby, below the pump,so this area is melted faster than the other areas.

It is the task of this invention to create an alternative solution forwarming a fluid in a vehicle.

In accordance with the invention, this task is solved with a containerof the type mentioned at the beginning by powering the heating elementfrom an electrical source of energy.

The invention relates to heating any kinds of fluids, including radiatorwater for the engine and the fuel. If the latter is diesel fuel, attemperatures below the freezing point it tends to flocculate, especiallywithout the addition of volatile hydrocarbons. The fluid can also beengine or hydraulic oil which loses the desired viscosity below certaintemperatures and becomes syrupy.

In particular, the fluid is intended for cleaning window panes,headlights or other signal lights of the vehicle. Fluids for cleaningother objects on or in the vehicle can also be foreseen.

By warming the fluid by means of an electrical energy source, it can beheated to the desired temperature independent of how long theinternal-combustion engine has been running or when it was ignited.Especially short after starting the vehicle, the driver wishes to freethe window panes of precipitation, in particular frozen precipitationand dirt. With state-of-the-art windshield wiper systems, the driver isdependent on already heated radiator water.

A further disadvantage of the state of the art is that after the engineis started, the heat flowing into the washing fluid is needed while theengine is still cold. Especially with performance-optimized engines,even a slight loss of heat delays the heating of the engine, so that itdoes not reach its optimal operating temperature as fast as desired.

Here, the invention alleviates the situation by heating the fluidelectrically. The electrical source of energy is the starter battery ofa vehicle or an additional battery, such as those employed in vehicleswith auxiliary heating. In particular with batteries to be used in thefuture which provide a voltage of 42 V, it is possible to electricallyheat a fluid, in particular the windshield wiper fluid, in the vehicle.

Thus, in accordance with this invention, either a container heater canbe activated in conjunction with the auxiliary heating at a point intime before the internal-combustion engine is started. Or the containerheater can be switched on when starting the internal-combustion engine.In either case, a frozen fluid is thawed within a short time. Inparticular, the wiper water is rapidly heated to 35° C., as is usualwith current automobiles.

This way, the invention is suitable for replacing the known systems forheating a fluid, based on the heat exchanger principle, and forsuggesting the implementation of a heatable container for vehicles; thecontainer ensures a rapid reaction to the starting of the engine,independent of the operational status of the engine, and it does notlimit other heating systems within the vehicle.

Advantageous extensions of the invention result from the subclaims andfrom the description in conjunction with the drawings.

It is advantageous to use the vehicle battery as the source of energy,because then no additional battery must be placed in the vehicle. Takinginto consideration the additional function of heating one or severalfluids, it can be arranged to install a vehicle battery with a highercapacity than that capacity which is otherwise usual for the given typeof vehicle.

In a further advantageous design of the container, the heating elementis permanently attached to the wall of the container. In particular, thecontainer can consist of two parts, so that the heater can be easilyattached to a lower container part. This results in designsimplifications when assembling the container and mounting it in thevehicle.

If the heater occupies the entire wall of a fluid container or thebottom area and the area of the side walls or only the bottom area orpart of the bottom of the container, then this ensures that the heaterwill quickly heat a large surface of the fluid. In particular, heatingcan take place near feed pumps, which can be placed in particular in thearea of the bottom or side walls, in which the fluid can besimultaneously pumped. A wiper water container, for instance, isequipped with three feed pumps, one each for the front pane, the hearpane and the front lamps and signal equipment of the vehicle.

If the heating element is designed as a thick-film heater with aresistor element, then technology can be used which is proven many timesin the design of water cookers or kitchen machines. Such a kitchenmachine is known from, for example, DE 102 26 939 A1.

In an advantageous alternative implementation, the container is equippedwith a heating element which protrudes into the container through anopening in the wall.

A special advantage of this solution is that an existing opening,usually used as a filling opening for adding consumed fluid, servesdouble duty. At the lid is placed a heating rod, heating plate, aheating filament, a heating coil or something similar, which ispreferably dimensioned such that it does not prevent complete removal ofthe lid from the container when adding fluid. These implementations ofthe invention also ensure that the heating element has as large an areaas possible. In particular, this can be achieved with a heating plateplaced preferably near a pump or several pumps (assuming there areseveral pumps in the vehicle).

The lid can be connected with the container by means of a screw, bayonetor snap-together joint, for instance. Wires on the outside of the lidconnect the heating element through the lid with the source ofelectrical energy.

The heating element can be designed in various ways; preferably, it isat least partially formed as a rod or plate.

In an advantageous implementation of the invention, the heating elementis shaped like a filament or spiral.

It is also advantageous to use a container with which the heatingelement includes a rod and a plate placed at one free end of the rod.

In a further advantageous implementation of the container, it isforeseen that the heating element is at least partially placed near afeed pump for pumping the fluid out of or into the container. Thiseliminates the problem that feed lines connected to the pumps can becomeclogged by lumps or particles of the fluid which have not yet melted.

It is also advantageous when an electrical battery on board a motorizedvehicle is employed as the source of energy. However, it is not ruledout that the vehicle is connected via an electrical lead with theelectrical power from a garage or building, for instance when thevehicle is in the garage.

In a special implementation of the invention, the heating element placedin the container is part of an electrical circuit including the energysource, for which a first switch (which can be operated by means ofignition equipment in order to ignite an internal-combustion engine), inparticular a relay, is placed between the heating element and the energysource. As current enters the circuit, this switch/relay is switched.This occurs, for instance, when the battery current begins to flowbecause the ignition key is inserted in the engine lock or the engine isswitched on.

It is also advantageous for control equipment (in particular, a secondswitch) controllable by the fluid's level to be placed in a circuitincluding the heating element and the energy source. This way,overheating of the heating element and hence the hazard of an electricalshort circuit can be prevented.

It is advantageous to have a first thermostat regulate the temperature,in order to determine the duration of heating and/or the heating energywith which the fluid in the container or in a supply line leading to thecontainer for feeding or removing the fluid is heated.

It is advantageous to arrange for the first thermostat to open orinterrupt the supply line above a specific temperature value. Forexample, a desirable temperature value would be 35° C., as is wanted formany common automobiles today. The fluid is heated as long as thetemperature is below 35° C. Since the heating takes place independent ofthe engine, there is no hazard of an engine malfunction. When atemperature of 35° C. is reached, the heating is switched off.

Additionally, in a further advantageous implementation of the container,it is foreseen that a second thermostat (serving as a safety thermostat)is inserted before the first thermostat; when a specific temperaturevalue is exceeded, this second thermostat switches the control equipmenton or off. In particular, it opens or closes the second switch. It isadvantageous for 50° C. to be selected for this temperature value.

This prevents the temperature of the fluid and container from increasingin an uncontrolled manner, by interrupting the supply of electricalenergy when a temperature of 50° C. is reached. A display unit can beforeseen, for example on the dashboard, which indicates to the driverwhenever the control thermostat fails.

A level sensor can be foreseen in the container, which interrupts theheating when the fluid level is too low. This information can beforwarded to the driver and displayed to him, for instance, on thedashboard.

It is advantageous to form the container as a blast-plastic part or asplastic injection molding part.

In one implementation of the invention, it is foreseen that thecontainer will feature a lower and upper part, and that the heatingelement will be placed at least in the lower part.

It is advantageous to embed at least one electrical heating filament (inparticular, a spiral-shaped one) in the wall of the lower part.

A level sensor can also be placed in the container.

Additionally, in accordance with the invention it can be foreseen thatlines for transporting the fluid and nozzles, to which the fluid istransported, are also heated.

The invention is explained in detail below, based on implementationexamples shown in the illustrations. They show:

FIG. 1 an electrical circuit for a heating element and

FIGS. 2-4 schematic views of containers with a heating element

A container 1 (FIG. 1) for a fluid to be heated in a vehicle contains anelectrical coil 2, connected via lead 3 with one of the poles 4 of asource of electrical energy 5. The other pole 6 is connected via anotherlead with the other terminal of the heating coil or with coil 2.

Another electrical lead connected to the source of electrical energy 5service as a control lead. It is connected with a relay 9 having aconnecting lead 7, in order to close the connecting lead when relay 9 isclosed, for instance when the engine is started and the battery currentflows.

A level sensor 10 is also inserted in the circuit of lead 8. Wheneverthe fluid in container 1 drops below a specified level, this sensoractuates a circuit breaker 11 in order to prevent the fluid in container1 from overheating and damaging the container. A display unit 12connected with the circuit breaker indicates to the driver that thefluid level is too low.

And, finally, in order to adhere to a minimum temperature of the fluidto be heated, another control thermometer 13 is inserted in lead 8. At aspecific temperature, it actuates and closes lead 8, which supplies coil2 with current. Hence, the temperature is maintained above a certainvalue, e.g., above 35° C.

In case thermostat 13 malfunctions, it must be prevented that coil 2will still be powered and continue to heat the fluid. For this reason, asafety thermostat 14 is inserted with thermostat 13. It drops out andopens the connection of the electrical lead 8 whenever a specifictemperature is exceeded. This temperature is much higher than thetemperature set at control thermostat 13. It can be set to, for example,50° C.

Of course, the circuit can be equipped with all kinds of display unitswhich serve other purposes. Examples are indicating battery failure orequipment for indicating the failure of control thermostat 13.

In one implementation of the invention (FIG. 2), a heating element 16(placed in a plastic container 15) features a cover plate 17 on theoutside wall 18 of container 15. The cover plate 17 protrudes beyond anopening (not shown) in the wall 18, through which a heating rod 19 isinserted. The cover plate 17 and the heating rod 19 in the area aroundwall 18 consist of thermally and electrically insulating material, sothat the plastic of wall 18 is not heated and cannot melt.

The inside of container 15 is filled at least partially with a fluid tobe heated. The fluid can be pumped by pumps 20, 21, 22 on the bottom ofthe container 15. It can be transported by supply lines to the washingequipment of the front and rear windshields as well as to the frontlamps and headlights of the vehicle.

Placing plate 23 near the pumps 20 through 22 ensures that these pumpsand the lines connected to them for transporting the fluid will notbecome clogged with frozen fluid particles. In addition, however, it canbe foreseen that heating elements are placed at the lines themselvesand/or at the outlet-side nozzles of the lines, from which the fluid issprayed onto the window panes or headlights.

The fluid is heated by both the heating rod 19 and a plate 23 at itslower end. A heating filament 24 runs through the heating rod 19 and theplate 23; at the plate 23 it is spirally shaped. The heating filament 24forms an ohmic resistance heater. The heating filament 24 is embedded inan electrically insulating material 25 within the heating rod 19 and theplate 23.

In a further implementation (FIG. 3), a loop-shaped heating rod 26 isplaced in the container 15, which is also inserted into the container 15via the cover plate 17 through an opening. Instead of a single loop, ofcourse there can be several loops, similar to a immersion heater.

In a further implementation (FIG. 4), a container 27 features a lid 28and a lower part 29. The lid 28 has a lug 30 through which the lid 28 isjoined with other design parts of the vehicle. An inlet port 31 foradding the fluid is also foreseen.

In its lower part 29, the container 27 features a wall made ofelectrically isolating, heat-resistant material, containing inside aheating filament 32 (shown in the exposed part of the lower part 29) inorder to heat the fluid in the container 27.

The outside wall of the lower part 29 and preferably also the outsidewall of the lid consists of thermally isolating material, to preventdissipation of the heat inside the container 27 and an undesired heatingof the surroundings of the container 27 in the vehicle.

The heater placed in the wall of the container 27 is designed as athick-film heater with a resistor element, for which thin heating tracksare pressed onto an enamel stainless steel plate facing the interior ofthe container 27. A protective coating is applied to the heating tracksfor passivating. For protection against mechanical and electricalinfluences from the outside of the container, the coating is covered byanother layer.

1. Container (1, 15) with a wall for accepting a fluid to be heated in avehicle, whereby the container (1, 15) features a heating element (16)characterized by the heating element (16) being fed from an electricalsource of energy.
 2. Container (1, 15) in accordance with claim 1,characterized by the source of energy being a vehicle battery. 3.Container (1, 15) in accordance with claim 1, characterized by a heatingelement (16) joined to a wall (18) of the container (1, 15). 4.Container (1, 15) in accordance with claim 3, characterized by a heatingelement (16) designed as a thick-film heater with a resistor element. 5.Container (1, 15) in accordance with claim 3, characterized by a heatingelement (16) protrudes into the container (1, 15) through an opening inthe wall (18) of the container (1, 15).
 6. Container (1, 15) inaccordance with claim 5, characterized by an opening which is a fillingopening for adding fluid to the container (1, 15).
 7. Container (1, 15)in accordance with claim 1, characterized by a heating element (16) atleast partially formed as a rod (19) or plate (23).
 8. Container (1, 15)in accordance with claim 1, characterized by a heating element (16)shaped like a filament or spiral.
 9. Container (1, 15) in accordancewith claim 7, characterized by a heating element (16) including aheating rod (19) and a plate (23) placed at one free end of the heatingrod (19).
 10. Container (1, 15) in accordance with claim 1,characterized by a heating element (16) at least partially near a feedpump (20, 21, 22) for transporting the fluid out of the container (1,15) or into it.
 11. Container (1, 15) in accordance with claim 1,characterized by the source of energy being an electrical battery onboard a motorized vehicle.
 12. Container (1, 15) in accordance withclaim 1, characterized by a first switch (in particular, a relay (9))operated by means of ignition equipment for igniting aninternal-combustion engine being placed in a circuit including theheating element (16) and the energy source, between the heating element(16) and the energy source.
 13. Container (1, 15) in accordance withclaim 1, characterized by control equipment (in particular, a secondswitch (10)) controllable by the fluid's level being placed in a circuitincluding the heating element (16) and the energy source.
 14. Container(1, 15) in accordance with claim 1, characterized by a first thermostat(13) for setting the temperature being placed in the container (1, 15)or in a supply line leading to the container (1, 15) for feeding orremoving the fluid.
 15. Container (1, 15) in accordance with claim 14,characterized by having the first thermostat (13) open or close thesupply line above a specific temperature value.
 16. Container (1, 15) inaccordance with claim 15, characterized by the temperature value being35° C.
 17. Container (1, 15) in accordance with claim 14, characterizedby a second thermostat (serving as a safety thermostat) being insertedbefore the first thermostat, when a specific temperature value isexceeded, this second thermostat switches the control equipment on oroff. In particular, it opens or closes a second switch.
 18. Container(1, 15) in accordance with claim 17, characterized by the temperaturevalue being 50° C.
 19. Container (1, 15) in accordance with claim 1,characterized by it being formed as a blast-plastic part or as plasticinjection molding part.
 20. Container (1, 15) in accordance with claim19, characterized by it featuring a lower (29) and upper part (28), withthe heating element (16) placed at least in the lower part (29). 21.Container (1, 15) in accordance with claim 20, characterized byembedding at least one electrical heating filament (32) (in particular,a spiral-shaped one) in the wall of the lower part (29).
 22. Container(1, 15) in accordance with claim 1, characterized by featuring a levelsensor (10).